Methods and apparatus for electromechanically and/or electrochemically-mechanically removing conductive material from a microelectronic substrate

ABSTRACT

Methods and apparatuses for electromechanically and/or electrochemically-mechanically removing conductive material from a microelectronic substrate. An apparatus in accordance with one embodiment includes a support member configured to releasably carry a microelectronic substrate and first and second electrodes spaced apart from each other and from the microelectronic substrate. A polishing medium is positioned between the electrodes and the support member and has a polishing surface positioned to contact the microelectronic substrate. At least a portion of the first and second electrodes can be recessed from the polishing surface. A liquid, such as an electrolytic liquid, can be provided in the recess, for example, through flow passages in the electrodes and/or the polishing medium. A variable electrical signal is passed from at least one of the electrodes, through the electrolyte and to the microelectronic substrate to remove material from the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/616,683 filed Dec. 27, 2006, which is a divisional of U.S. patentapplication Ser. No. 10/230,970 filed Aug. 29, 2002, now U.S. Pat. No.7,220,166, both of which are incorporated herein by reference. U.S.patent application Ser. No. 10/230,970 is a continuation-in-part of thefollowing U.S. patent applications, all of which are incorporated hereinby reference: Ser. No. 09/651,779, filed Aug. 30, 2000, now U.S. Pat.No. 7,074,113, Ser. No. 09/888,084, filed Jun. 21, 2001, now U.S. Pat.No. 7,112,121, Ser. No. 09/887,767, filed Jun. 21, 2001, now U.S. Pat.No. 7,094,131, and Ser. No. 09/888,002, filed Jun. 21, 2001, now U.S.Pat. No. 7,160,176. This application is also related to the followingU.S. patent applications, filed Aug. 29, 2002 and incorporated herein byreference: Ser. No. 10/230,972, now U.S. Pat. No. 7,134,934; Ser. No.10/230,973, now U.S. Pat. No. 7,153,195; Ser. No. 10/230,463, now U.S.Pat. No. 7,192,335; and Ser. No. 10/230,628, now U.S. Pat. No.7,078,308.

TECHNICAL FIELD

This invention relates to methods and apparatuses forelectromechanically and/or electrochemically-mechanically removingconductive material from microelectronic substrates.

BACKGROUND

Microelectronic substrates and substrate assemblies typically include asemiconductor material having features, such as memory cells, that arelinked with conductive lines. The conductive lines can be formed byfirst forming trenches or other recesses in the semiconductor material,and then overlaying a conductive material (such as a metal) in thetrenches. The conductive material is then selectively removed to leaveconductive lines extending from one feature in the semiconductormaterial to another.

Electrolytic techniques have been used to both deposit and removemetallic layers from semiconductor substrates. For example, analternating current can be applied to a conductive layer via anintermediate electrolyte to remove portions of the layer. In onearrangement, shown in FIG. 1, a conventional apparatus 60 includes afirst electrode 20 a and a second electrode 20 b coupled to a currentsource 21. The first electrode 20 a is attached directly to a metalliclayer 11 of a semiconductor substrate 10 and the second electrode 20 bis at least partially immersed in a liquid electrolyte 31 disposed onthe surface of the metallic layer 11 by moving the second electrodedownwardly until it contacts the electrolyte 31. A barrier 22 protectsthe first electrode 20 a from direct contact with the electrolyte 31.The current source 21 applies alternating current to the substrate 10via the electrodes 20 a and 20 b and the electrolyte 31 to removeconductive material from the conductive layer 11. The alternatingcurrent signal can have a variety of wave forms, such as those disclosedby Frankenthal et al. in a publication entitled, “Electroetching ofPlatinum in the Titanium-Platinum-Gold Metallization on SiliconIntegrated Circuits” (Bell Laboratories), incorporated herein in itsentirety by reference.

One drawback with the arrangement shown in FIG. 1 is that it may not bepossible to remove material from the conductive layer 11 in the regionwhere the first electrode 20 a is attached because the barrier 22prevents the electrolyte 31 from contacting the substrate 10 in thisregion. Alternatively, if the first electrode 20 a contacts theelectrolyte in this region, the electrolytic process can degrade thefirst electrode 20 a. Still a further drawback is that the electrolyticprocess may not uniformly remove material from the substrate 10. Forexample, “islands” of residual conductive material having no directelectrical connection to the first electrode 20 a may develop in theconductive layer 11. The residual conductive material can interfere withthe formation and/or operation of the conductive lines, and it may bedifficult or impossible to remove with the electrolytic process unlessthe first electrode 20 a is repositioned to be coupled to such“islands.”

One approach to addressing some of the foregoing drawbacks is to attacha plurality of first electrodes 20 a around the periphery of thesubstrate 10 to increase the uniformity with which the conductivematerial is removed. However, islands of conductive material may stillremain despite the additional first electrodes 20 a. Another approach isto form the electrodes 20 a and 20 b from an inert material, such ascarbon, and remove the barrier 22 to increase the area of the conductivelayer 11 in contact with the electrolyte 31. However, such inertelectrodes may not be as effective as more reactive electrodes atremoving the conductive material, and the inert electrodes may stillleave residual conductive material on the substrate 10.

FIG. 2 shows still another approach to addressing some of the foregoingdrawbacks in which two substrates 10 are partially immersed in a vessel30 containing the electrolyte 31. The first electrode 20 a is attachedto one substrate 10 and the second electrode 20 b is attached to theother substrate 10. An advantage of this approach is that the electrodes20 a and 20 b do not contact the electrolyte. However, islands ofconductive material may still remain after the electrolytic process iscomplete, and it may be difficult to remove conductive material from thepoints at which the electrodes 20 a and 20 b are attached to thesubstrates 10.

SUMMARY

The present invention is directed toward methods and apparatuses forelectromechanically and/or electrochemically-mechanically removingconductive material from a microelectronic substrate. An apparatus inaccordance with one aspect of the invention includes a support memberconfigured to releasably carry a microelectronic substrate. First andsecond electrodes are positioned to be spaced apart from each other andfrom the microelectronic substrate when the microelectronic substrate iscarried by the support member. At least one of the electrodes iscoupleable to a source of varying electrical signals. A polishingmedium, at least a portion of which is positioned between the electrodesand the support member, includes a polishing surface positioned tocontact the microelectronic substrate when the microelectronic substrateis carried by the support member. At least a portion of the first andsecond electrodes is recessed from the polishing surface.

In another aspect of the invention, the apparatus can include flowpassages to provide a liquid, such as an electrolytic liquid, at leastproximate to an interface between the polishing surface and themicroelectronic substrate. For example, the flow passages can bepositioned in the polishing medium and/or in at least one of the firstand second electrodes. In yet a further aspect of the invention, theflow passages can include apertures that are recessed from the polishingsurface of the polishing medium.

A method for removing material from a microelectronic substrate inaccordance with yet another aspect of the invention includes positioningthe microelectronic substrate proximate to and spaced apart from thefirst and second electrodes, with the first and second electrodeselongated along first and second axes, respectively. The method canfurther include moving the microelectronic substrate relative to thefirst and second electrodes in a direction transverse to at least one ofthe first and second axes, while passing a variable electrical signalthrough the first and second electrodes and the microelectronicsubstrate.

A method in accordance with still another aspect of the inventionincludes contacting the microelectronic substrate with a polishingsurface of a polishing medium, positioning the microelectronic substrateproximate to and spaced apart from first and second electrodes, whichare in turn spaced apart from each other and recessed from the polishingsurface. The method can further include moving the microelectronicsubstrate relative to the first and second electrodes while passing avariable electrical signal through the electrodes and themicroelectronic substrate. In still a further aspect of the invention, aliquid, such as an electrolytic liquid, can be introduced into a regionat least proximate to an interface between the polishing surface and themicroelectronic substrate through the first electrode, the secondelectrode, and/or the polishing medium.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially schematic, side elevational view of an apparatusfor removing conductive material from a semiconductor substrate inaccordance with the prior art.

FIG. 2 is a partially schematic side, elevational view of anotherapparatus for removing conductive material from two semiconductorsubstrates in accordance with the prior art.

FIG. 3 is a partially schematic, side elevational view of an apparatushaving a support member and a pair of electrodes for removing conductivematerial from a microelectronic substrate in accordance with anembodiment of the invention.

FIG. 4 is a partially schematic, side elevational view of an apparatusfor removing conductive material and sensing characteristics of themicroelectronic substrate from which the material is removed inaccordance with another embodiment of the invention.

FIG. 5 is a partially schematic, side elevational view of an apparatusthat includes two electrolytes in accordance with still anotherembodiment of the invention.

FIG. 6 is a partially schematic, plan view of a substrate adjacent to aplurality of electrodes in accordance with still further embodiments ofthe invention.

FIG. 7 is a cross-sectional, side elevational view of an electrode and asubstrate in accordance with yet another embodiment of the invention.

FIG. 8A is a partially schematic, isometric view of a portion of asupport for housing electrode pairs in accordance with still anotherembodiment of the invention.

FIGS. 8B-8C are isometric views of electrodes in accordance with stillfurther embodiments of the invention.

FIG. 9 is a partially schematic, side elevational view of an apparatusfor both planarizing and electrolytically processing microelectronicsubstrates in accordance with yet another embodiment of the invention.

FIG. 10 is a partially schematic, partially exploded isometric view of aplanarizing pad and a plurality of electrodes in accordance with stillanother embodiment of the invention.

FIG. 11 is a partially schematic, side elevational view of an apparatusfor both planarizing and electrolytically processing microelectronicsubstrates in accordance with still another embodiment of the invention.

FIGS. 12A-B schematically illustrate a circuit and wave form forelectrolytically processing a microelectronic substrate in accordancewith yet another embodiment of the invention.

FIG. 13 is an isometric, partially schematic, partially cutaway view ofa portion of an apparatus having electrodes and a polishing medium inaccordance with an embodiment of the invention.

FIG. 14 is an isometric, partially schematic, partially cutaway view ofan apparatus having electrodes and a polishing medium in accordance withanother embodiment of the invention.

FIG. 15 is an isometric, partially schematic, partially cutawayisometric view of an apparatus having electrodes and a polishing mediumin accordance with still another embodiment of the invention.

FIG. 16 is an isometric, partially schematic, partially cutaway view ofan apparatus having a polishing medium with oval apertures in accordancewith yet another embodiment of the invention.

FIG. 17 is an isometric view of an apparatus supporting a substrate formotion along a path in accordance with another embodiment of theinvention.

FIG. 18 is an isometric view of an apparatus having electrodes orientedin accordance with still another embodiment of the invention.

DETAILED DESCRIPTION

The present disclosure describes methods and apparatuses for removingconductive materials from a microelectronic substrate and/or substrateassembly used in the fabrication of microelectronic devices. Manyspecific details of certain embodiments of the invention are set forthin the following description and in FIGS. 3-18 to provide a thoroughunderstanding of these embodiments. One skilled in the art, however,will understand that the present invention may have additionalembodiments, or that the invention may be practiced without several ofthe details described below.

FIG. 3 is a partially schematic, side elevational view of an apparatus160 for removing conductive material from a microelectronic substrate orsubstrate assembly 110 in accordance with an embodiment of theinvention. In one aspect of this embodiment, the apparatus 160 includesa vessel 130 containing an electrolyte 131, which can be in a liquid ora gel state. A support member 140 supports the microelectronic substrate110 relative to the vessel 130 so that a conductive layer 111 of thesubstrate 110 contacts the electrolyte 131. The conductive layer 111 caninclude metals such as platinum, tungsten, tantalum, gold, copper, orother conductive materials. In another aspect of this embodiment, thesupport member 140 is coupled to a substrate drive unit 141 that movesthe support member 140 and the substrate 110 relative to the vessel 130.For example, the substrate drive unit 141 can translate the supportmember 140 (as indicated by arrow “A”) and/or rotate the support member140 (as indicated by arrow “B”).

The apparatus 160 can further include a first electrode 120 a and asecond electrode 120 b (referred to collectively as electrodes 120)supported relative to the microelectronic substrate 110 by a supportmember 124. In one aspect of this embodiment, the support arm 124 iscoupled to an electrode drive unit 123 for moving the electrodes 120relative to the microelectronic substrate 110. For example, theelectrode drive unit 123 can move the electrodes toward and away fromthe conductive layer 111 of the microelectronic substrate 110, (asindicated by arrow “C”), and/or transversely (as indicated by arrow “D”)in a plane generally parallel to the conductive layer 111.Alternatively, the electrode drive unit 123 can move the electrodes inother fashions, or the electrode drive unit 123 can be eliminated whenthe substrate drive unit 141 provides sufficient relative motion betweenthe substrate 110 and the electrodes 120.

In either embodiment described above with reference to FIG. 3, theelectrodes 120 are coupled to a current source 121 with leads 128 forsupplying electrical current to the electrolyte 131 and the conductivelayer 111. In operation, the current source 121 supplies an alternatingcurrent (single phase or multiphase) to the electrodes 120. The currentpasses through the electrolyte 131 and reacts electrochemically with theconductive layer 111 to remove material (for example, atoms or groups ofatoms) from the conductive layer 111. The electrodes 120 and/or thesubstrate 110 can be moved relative to each other to remove materialfrom selected portions of the conductive layer 111, or from the entireconductive layer 111.

In one aspect of an embodiment of the apparatus 160 shown in FIG. 3, adistance D₁ between the electrodes 120 and the conductive layer 111 isset to be smaller than a distance D₂ between the first electrode 120 aand the second electrode 120 b. Furthermore, the electrolyte 131generally has a higher resistance than the conductive layer 111.Accordingly, the alternating current follows the path of leastresistance from the first electrode 120 a, through the electrolyte 131to the conductive layer 111 and back through the electrolyte 131 to thesecond electrode 120 b, rather than from the first electrode 120 adirectly through the electrolyte 131 to the second electrode 120 b.Alternatively, a low dielectric material (not shown) can be positionedbetween the first electrode 120 a and the second electrode 120 b todecouple direct electrical communication between the electrodes 120 thatdoes not first pass through the conductive layer 111.

One feature of an embodiment of the apparatus 160 shown in FIG. 3 isthat the electrodes 120 do not contact the conductive layer 111 of thesubstrate 110. An advantage of this arrangement is that it can eliminatethe residual conductive material resulting from a direct electricalconnection between the electrodes 120 and the conductive layer 111,described above with reference to FIGS. 1 and 2. For example, theapparatus 160 can eliminate residual conductive material adjacent to thecontact region between the electrodes and the conductive layer becausethe electrodes 120 do not contact the conductive layer 111.

Another feature of an embodiment of the apparatus 160 described abovewith reference to FIG. 3 is that the substrate 110 and/or the electrodes120 can move relative to the other to position the electrodes 120 at anypoint adjacent to the conductive layer 111. An advantage of thisarrangement is that the electrodes 120 can be sequentially positionedadjacent to every portion of the conductive layer to remove materialfrom the entire conductive layer 111. Alternatively, when it is desiredto remove only selected portions of the conductive layer 111, theelectrodes 120 can be moved to those selected portions, leaving theremaining portions of the conductive layer 111 intact.

FIG. 4 is a partially schematic, side elevational view of an apparatus260 that includes a support member 240 positioned to support thesubstrate 110 in accordance with another embodiment of the invention. Inone aspect of this embodiment, the support member 240 supports thesubstrate 110 with the conductive layer 111 facing upwardly. A substratedrive unit 241 can move the support member 240 and the substrate 110, asdescribed above with reference to FIG. 3. First and second electrodes220 a and 220 b are positioned above the conductive layer 111 and arecoupled to a current source 221. A support member 224 supports theelectrodes 220 relative to the substrate 110 and is coupled to anelectrode drive unit 223 to move the electrodes 220 over the surface ofthe support conductive layer 111 in a manner generally similar to thatdescribed above with reference to FIG. 3.

In one aspect of the embodiment shown in FIG. 4, the apparatus 260further includes an electrolyte vessel 230 having a supply conduit 237with an aperture 238 positioned proximate to the electrodes 220.Accordingly, an electrolyte 231 can be deposited locally in an interfaceregion 239 between the electrodes 220 and the conductive layer 111,without necessarily covering the entire conductive layer 111. Theelectrolyte 231 and the conductive material removed from the conductivelayer 111 flow over the substrate 110 and collect in an electrolytereceptacle 232. The mixture of electrolyte 231 and conductive materialcan flow to a reclaimer 233 that removes most of the conductive materialfrom the electrolyte 231. A filter 234 positioned downstream of thereclaimer 233 provides additional filtration of the electrolyte 231 anda pump 235 returns the reconditioned electrolyte 231 to the electrolytevessel 230 via a return line 236.

In another aspect of the embodiment shown in FIG. 4, the apparatus 260can include a sensor assembly 250 having a sensor 251 positionedproximate to the conductive layer 111, and a sensor control unit 252coupled to the sensor 251 for processing signals generated by the sensor251. The control unit 252 can also move the sensor 251 relative to thesubstrate 110. In a further aspect of this embodiment, the sensorassembly 250 can be coupled via a feedback path 253 to the electrodedrive unit 223 and/or the substrate drive unit 241. Accordingly, thesensor 251 can determine which areas of the conductive layer 111 requireadditional material removal and can move the electrodes 220 and/or thesubstrate 110 relative to each other to position the electrodes 220 overthose areas. Alternatively, (for example, when the removal process ishighly repeatable), the electrodes 220 and/or the substrate 110 can moverelative to each other according to a pre-determined motion schedule.

The sensor 251 and the sensor control unit 252 can have any of a numberof suitable configurations. For example, in one embodiment, the sensor251 can be an optical sensor that detects removal of the conductivelayer 111 by detecting a change in the intensity, wavelength or phaseshift of the light reflected from the substrate 110 when the conductivematerial is removed. Alternatively, the sensor 251 can emit and detectreflections of radiation having other wavelengths, for example, x-rayradiation. In still another embodiment, the sensor 251 can measure achange in resistance or capacitance of the conductive layer 111 betweentwo selected points. In a further aspect of this embodiment, one or bothof the electrodes 220 can perform the function of the sensor 251 (aswell as the material removal function described above), eliminating theneed for a separate sensor 251. In still further embodiments, the sensor251 can detect a change in the voltage and/or current drawn from thecurrent supply 221 as the conductive layer 111 is removed.

In any of the embodiments described above with reference to FIG. 4, thesensor 251 can be positioned apart from the electrolyte 231 because theelectrolyte 231 is concentrated in the interface region 239 between theelectrodes 220 and the conductive layer 111. Accordingly, the accuracywith which the sensor 251 determines the progress of the electrolyticprocess can be improved because the electrolyte 231 will be less likelyto interfere with the operation of the sensor 251. For example, when thesensor 251 is an optical sensor, the electrolyte 231 will be less likelyto distort the radiation reflected from the surface of the substrate 110because the sensor 251 is positioned away from the interface region 239.

Another feature of an embodiment of the apparatus 260 described abovewith reference to FIG. 4 is that the electrolyte 231 supplied to theinterface region 239 is continually replenished, either with areconditioned electrolyte or a fresh electrolyte. An advantage of thisfeature is that the electrochemical reaction between the electrodes 220and the conductive layer 111 can be maintained at a high and consistentlevel.

FIG. 5 is a partially schematic, side elevational view of an apparatus360 that directs alternating current to the substrate 110 through afirst electrolyte 331 a and a second electrolyte 331 b. In one aspect ofthis embodiment, the first electrolyte 331 a is disposed in two firstelectrolyte vessels 330 a, and the second electrolyte 331 b is disposedin a second electrolyte vessel 330 b. The first electrolyte vessels 330a are partially submerged in the second electrolyte 331 b. The apparatus360 can further include electrodes 320, shown as a first electrode 320 aand a second electrode 320 b, each coupled to a current supply 321 andeach housed in one of the first electrolyte vessels 330 a.Alternatively, one of the electrodes 320 can be coupled to ground. Theelectrodes 320 can include materials such as silver, platinum, copperand/or other materials, and the first electrolyte 331 a can includesodium chloride, potassium chloride, copper sulfate and/or otherelectrolytes that are compatible with the material forming theelectrodes 320.

In one aspect of this embodiment, the first electrolyte vessels 330 ainclude a flow restrictor 322, such as a permeable isolation membraneformed from Teflon™, sintered materials such as sintered glass, quartzor sapphire, or other suitable porous materials that allow ions to passback and forth between the first electrolyte vessels 330 a and thesecond electrolyte vessel 330 b, but do not allow the second electrolyte330 b to pass inwardly toward the electrodes 320 (for example, in amanner generally similar to a salt bridge).

Alternatively, the first electrolyte 331 a can be supplied to theelectrode vessels 330 a from a first electrolyte source 339 at apressure and rate sufficient to direct the first electrolyte 331 aoutwardly through the flow restrictor 322 without allowing the firstelectrolyte 331 a or the second electrolyte 330 b to return through theflow restrictor 322. In either embodiment, the second electrolyte 331 bremains electrically coupled to the electrodes 320 by the flow of thefirst electrolyte 331 a through the restrictor 322.

In one aspect of this embodiment, the apparatus 360 can also include asupport member 340 that supports the substrate 110 with the conductivelayer 111 facing toward the electrodes 320. For example, the supportmember 340 can be positioned in the second electrolyte vessel 330 b. Ina further aspect of this embodiment, the support member 340 and/or theelectrodes 320 can be movable relative to each other by one or moredrive units (not shown).

One feature of an embodiment of the apparatus 360 described above asreference to FIG. 5 is that the first electrolyte 331 a can be selectedto be compatible with the electrodes 320. An advantage of this featureis that the first electrolyte 331 a can be less likely than conventionalelectrolytes to degrade the electrodes 320. Conversely, the secondelectrolyte 331 b can be selected without regard to the effect it has onthe electrodes 320 because it is chemically isolated from the electrodes320 by the flow restrictor 322. Accordingly, the second electrolyte 331b can include hydrochloric acid or another agent that reactsaggressively with the conductive layer 111 of the substrate 110.

FIG. 6 is a top plan view of the microelectronic substrate 110positioned beneath a plurality of electrodes having shapes andconfigurations in accordance with several embodiments of the invention.For purposes of illustration, several different types of electrodes areshown positioned proximate to the same microelectronic substrate 110;however, in practice, electrodes of the same type can be positionedrelative to a single microelectronic substrate 110.

In one embodiment, electrodes 720 a and 720 b can be grouped to form anelectrode pair 770 a, with each electrode 720 a and 720 b coupled to anopposite terminal of a current supply 121 (FIG. 3). The electrodes 770 aand 770 b can have an elongated or strip-type shape and can be arrangedto extend parallel to each other over the diameter of the substrate 110.The spacing between adjacent electrodes of an electrode pair 370 a canbe selected to direct the electrical current into the substrate 110, asdescribed above with reference to FIG. 3.

In an alternate embodiment, electrodes 720 c and 720 d can be grouped toform an electrode pair 770 b, and each electrode 720 c and 720 d canhave a wedge or “pie” shape that tapers inwardly toward the center ofthe microelectronic substrate 110. In still another embodiment, narrow,strip-type electrodes 720 e and 720 f can be grouped to form electrodepairs 770 c, with each electrode 720 e and 720 f extending radiallyoutwardly from the center 113 of the microelectronic substrate 110toward the periphery 112 of the microelectronic substrate 110.

In still another embodiment, a single electrode 720 g can extend overapproximately half the area of the microelectronic substrate 110 and canhave a semicircular planform shape. The electrode 720 g can be groupedwith another electrode (not shown) having a shape corresponding to amirror image of the electrode 720 g, and both electrodes can be coupledto the current source 121 to provide alternating current to themicroelectronic substrate in any of the manners described above withreference to FIGS. 3-5.

FIG. 7 is a partially schematic, cross-sectional side elevational viewof a portion of the substrate 110 positioned beneath the electrode 720 cdescribed above with reference to FIG. 6. In one aspect of thisembodiment, the electrode 720 c has an upper surface 771 and a lowersurface 772 opposite the upper surface 771 and facing the conductivelayer 111 of the substrate 110. The lower surface 772 can taperdownwardly from the center 113 of the substrate 110 toward the perimeter112 of the substrate 110 in one aspect of this embodiment to give theelectrode 720 c a wedge-shaped profile. Alternatively, the electrode 720c can have a plate-type configuration with the lower surface 772positioned as shown in FIG. 7 and the upper surface 771 parallel to thelower surface 772. One feature of either embodiment is that theelectrical coupling between the electrode 720 c and the substrate 110can be stronger toward the periphery 112 of the substrate 110 thantoward the center 113 of the substrate 110. This feature can beadvantageous when the periphery 112 of the substrate 110 moves relativeto the electrode 720 c at a faster rate than does the center 113 of thesubstrate 110, for example, when the substrate 110 rotates about itscenter 113. Accordingly, the electrode 720 c can be shaped to accountfor relative motion between the electrode and the substrate 110.

In other embodiments, the electrode 720 c can have other shapes. Forexample, the lower surface 772 can have a curved rather than a flatprofile. Alternatively, any of the electrodes described above withreference to FIG. 6 (or other electrodes having shapes other than thoseshown in FIG. 6) can have a sloped or curved lower surface. In stillfurther embodiments, the electrodes can have other shapes that accountfor relative motion between the electrodes and the substrate 110.

FIG. 8A is a partially schematic view of an electrode support 473 forsupporting a plurality of electrodes in accordance with anotherembodiment of the invention. In one aspect of this embodiment, theelectrode support 473 can include a plurality of electrode apertures474, each of which houses either a first electrode 420 a or a secondelectrode 420 b. The first electrodes 420 a are coupled through theapertures 474 to a first lead 428 a and the second electrodes 420 b arecoupled to a second lead 428 b. Both of the leads 428 a and 428 b arecoupled to a current supply 421. Accordingly, each pair 470 of first andsecond electrodes 420 a and 420 b defines part of a circuit that iscompleted by the substrate 110 and the electrolyte(s) described abovewith reference to FIGS. 3-5.

In one aspect of this embodiment, the first lead 428 a can be offsetfrom the second lead 428 b to reduce the likelihood for short circuitsand/or capacitive coupling between the leads. In a further aspect ofthis embodiment, the electrode support 473 can have a configurationgenerally similar to any of those described above with reference toFIGS. 1-7. For example, any of the individual electrodes (e.g., 320 a,320 c, 320 e, or 320 g) described above with reference to FIG. 6 can bereplaced with an electrode support 473 having the same overall shape andincluding a plurality of apertures 474, each of which houses one of thefirst electrodes 420 a or the second electrodes 420 b. In another aspectof this embodiment, the electrode support 473 can be configured tomechanically remove material from the microelectronic substrate, forexample, in a manner generally similar to that described below withreference to FIGS. 9-11 and 13-18.

In still a further aspect of this embodiment, the electrode pairs 470shown in FIG. 8A can be arranged in a manner that corresponds to theproximity between the electrodes 420 a, 420 b and the microelectronicsubstrate 110 (FIG. 7), and/or the electrode pairs 470 can be arrangedto correspond to the rate of relative motion between the electrodes 420a, 420 b and the microelectronic substrate 110. For example, theelectrode pairs 470 can be more heavily concentrated in the periphery112 of the substrate 110 or other regions where the relative velocitybetween the electrode pairs 470 and the substrate 110 is relatively high(see FIG. 7). Accordingly, the increased concentration of electrodepairs 470 can provide an increased electrolytic current to compensatefor the high relative velocity. Furthermore, the first electrode 420 aand the second electrode 420 b of each electrode pair 470 can berelatively close together in regions (such as the periphery 112 of thesubstrate 110) where the electrodes are close to the conductive layer111 (see FIG. 7) because the close proximity to the conductive layer 111reduces the likelihood for direct electrical coupling between the firstelectrode 420 a and the second electrode 420 b. In still a furtheraspect of this embodiment, the amplitude, frequency and/or waveformshape supplied to different electrode pairs 470 can vary depending onfactors such as the spacing between the electrode pair 470 and themicroelectronic substrate 110, and the relative velocity between theelectrode pair 470 and the microelectronic substrate 110.

FIGS. 8B-8C illustrate electrodes 820 (shown as first electrodes 820 aand second electrodes 820 b) arranged concentrically in accordance withstill further embodiments of the invention. In one embodiment shown inFIG. 8B, the first electrode 820 a can be positioned concentricallyaround the second electrode 820 b, and a dielectric material 829 can bedisposed between the first electrode 820 a and the second electrode 820b. The first electrode 820 a can define a complete 360° arc around thesecond electrode 820 b, as shown in FIG. 8B, or alternatively, the firstelectrode 820 a can define an arc of less than 360°.

In another embodiment, shown in FIG. 8C, the first electrode 820A can beconcentrically disposed between two second electrodes 820 b, with thedielectric material 829 disposed between neighboring electrodes 820. Inone aspect of this embodiment, current can be supplied to each of thesecond electrodes 820 b with no phase shifting. Alternatively, thecurrent supplied to one second electrode 820 b can be phase-shiftedrelative to the current supplied to the other second electrode 820 b. Ina further aspect of the embodiment, the current supplied to each secondelectrode 820 b can differ in characteristics other than phase, forexample, amplitude.

One feature of the electrodes 820 described above with respect to FIGS.8B-8C is that the first electrode 820 a can shield the secondelectrode(s) 820 b from interference from other current sources. Forexample, the first electrode 820 a can be coupled to ground to shieldthe second electrodes 820 b. An advantage of this arrangement is thatthe current applied to the substrate 110 (FIG. 7) via the electrodes 820can be more accurately controlled.

FIG. 9 schematically illustrates an apparatus 560 for both planarizingand electrolytically processing the microelectronic substrate 110 inaccordance with an embodiment of the invention. In one aspect of thisembodiment, the apparatus 560 has a support table 580 with a top-panel581 at a workstation where an operative portion “W” of a planarizing pad582 is positioned. The top-panel 581 is generally a rigid plate toprovide a flat, solid surface to which a particular section of theplanarizing pad 582 may be secured during planarization.

The apparatus 560 can also have a plurality of rollers to guide,position and hold the planarizing pad 582 over the top-panel 581. Therollers can include a supply roller 583, first and second idler rollers584 a and 584 b, first and second guide rollers 585 a and 585 b, and atake-up roller 586. The supply roller 583 carries an unused orpre-operative portion of the planarizing pad 582, and the take-up roller583 carries a used or post-operative portion of the planarizing pad 582.Additionally, the first idler roller 584 a and the first guide roller585 a can stretch the planarizing pad 582 over the top-panel 581 to holdthe planarizing pad 582 stationary during operation. A motor (not shown)drives at least one of the supply roller 583 and the take-up roller 586to sequentially advance the planarizing pad 582 across the top-panel581. Accordingly, clean pre-operative sections of the planarizing pad582 may be quickly substituted for used sections to provide a consistentsurface for planarizing and/or cleaning the substrate 110.

The apparatus 560 can also have a carrier assembly 590 that controls andprotects the substrate 110 during planarization. The carrier assembly590 can include a substrate holder 592 to pick up, hold and release thesubstrate 110 at appropriate stages of the planarizing process. Thecarrier assembly 590 can also have a support gantry 594 carrying a driveassembly 595 that can translate along the gantry 594. The drive assembly595 can have an actuator 596, a drive shaft 597 coupled to the actuator596, and an arm 598 projecting from the drive shaft 597. The arm 598carries the substrate holder 592 via a terminal shaft 599 such that thedrive assembly 595 orbits the substrate holder 592 about an axis E-E (asindicated by arrow “R₁”). The terminal shaft 599 may also rotate thesubstrate holder 592 about its central axis F-F (as indicated by arrow“R₂”).

The planarizing pad 582 and a planarizing solution 587 define aplanarizing medium that mechanically and/or chemically-mechanicallyremoves material from the surface of the substrate 110. The planarizingpad 582 used in the apparatus 560 can be a fixed-abrasive planarizingpad in which abrasive particles are fixedly bonded to a suspensionmedium. Accordingly, the planarizing solution 587 can be a “cleansolution” without abrasive particles because the abrasive particles arefixedly distributed across a planarizing surface 588 of the planarizingpad 582. In other applications, the planarizing pad 582 may be anon-abrasive pad without abrasive particles, and the planarizingsolution 587 can be a slurry with abrasive particles and chemicals toremove material from the substrate 110.

To planarize the substrate 110 with the apparatus 560, the carrierassembly 590 presses the substrate 110 against the planarizing surface588 of the planarizing pad 582 in the presence of the planarizingsolution 587. The drive assembly 595 then orbits the substrate holder592 about the axis E-E and optionally rotates the substrate holder 592about the axis F-F to translate the substrate 110 across the planarizingsurface 588. As a result, the abrasive particles and/or the chemicals inthe planarizing medium remove material from the surface of the substrate110 in a chemical and/or chemical-mechanical planarization (CMP)process. Accordingly, the planarizing pad 582 can smooth the substrate110 by removing rough features projecting from the conductive layer 111of the substrate 110.

In a further aspect of this embodiment, the apparatus 560 can include anelectrolyte supply vessel 530 that delivers an electrolyte to theplanarizing surface of the planarizing pad 582 with a conduit 537, asdescribed in greater detail with reference to FIG. 10. The apparatus 560can further include a current supply 521 coupled to the support table580 and/or the top-panel 581 to supply an electrical current toelectrodes positioned in the support table 580 and/or the top-panel 581.Accordingly, the apparatus 560 can electrolytically remove material fromthe conductive layer 111 in a manner similar to that described abovewith reference to FIGS. 1-8C.

In one aspect of an embodiment of the apparatus 560 described above withreference to FIG. 9, material can be sequentially removed from theconductive layer 111 of the substrate 110 first by an electrolyticprocess and then by a CMP process. For example, the electrolytic processcan remove material from the conductive layer 111 in a manner thatroughens the conductive layer 111. After a selected period ofelectrolytic processing time has elapsed, the electrolytic processingoperation can be halted and additional material can be removed via CMPprocessing. Alternatively, the electrolytic process and the CMP processcan be conducted simultaneously. In either of these processingarrangements, one feature of an embodiment of the apparatus 560described above with reference to FIG. 9 is that the same apparatus 560can planarize the substrate 110 via CMP and remove material from thesubstrate 110 via an electrolytic process. An advantage of thisarrangement is that the substrate 110 need not be moved from oneapparatus to another to undergo both CMP and electrolytic processing.

Another advantage of an embodiment of the apparatus 560 described abovewith reference to FIG. 9 is that the processes, when used in conjunctionwith each other, is expected to remove material from the substrate 110more quickly and accurately than some conventional processes. Forexample, as described above, the electrolytic process can removerelatively large amounts of material in a manner that roughens themicroelectronic substrate 110, and the planarizing process can removematerial on a finer scale in a manner that smoothes and/or flattens themicroelectronic substrate 110.

FIG. 10 is a partially exploded, partially schematic isometric view of aportion of the apparatus 560 described above with reference to FIG. 9.In one aspect of an embodiment shown in FIG. 10, the top-panel 581houses a plurality of electrode pairs 570, each of which includes afirst electrode 520 a and a second electrode 520 b. The first electrodes520 a are coupled to a first lead 528 a and the second electrodes 520 bare coupled to a second lead 528 b. The first and second leads 528 a and528 b are coupled to the current source 521 (FIG. 9). In one aspect ofthis embodiment, the first electrode 520 a can be separated from thesecond electrodes 520 b by an electrode dielectric layer 529 a thatincludes Teflon™ or another suitable dielectric material. The electrodedielectric layer 529 a can accordingly control the volume and dielectricconstant of the region between the first and second electrodes 520 a and520 b to control electrical coupling between the electrodes.

The electrodes 520 a and 520 b can be electrically coupled to themicroelectronic substrate 110 (FIG. 9) by the planarizing pad 582. Inone aspect of this embodiment, the planarizing pad 582 is saturated withan electrolyte 531 supplied by the supply conduits 537 through apertures538 in the top-panel 581 just beneath the planarizing pad 582.

Accordingly, the electrodes 520 a and 520 b are selected to becompatible with the electrolyte 531. In an alternate arrangement, theelectrolyte 531 can be supplied to the planarizing pad 582 from above(for example, by disposing the electrolyte 531 in the planarizing liquid587) rather than through the top-panel 581. Accordingly, the planarizingpad 582 can include a pad dielectric layer 529 b positioned between theplanarizing pad 582 and the electrodes 520 a and 520 b. When the paddielectric layer 529 b is in place, the electrodes 520 a and 520 b areisolated from physical contact with the electrolyte 531 and canaccordingly be selected from materials that are not necessarilycompatible with the electrolyte 531.

In either of the embodiments described above with reference to FIG. 10,the planarizing pad 582 can provide several advantages over someconventional electrolytic arrangements. For example, the planarizing pad582 can uniformly separate the electrodes 520 a and 520 b from themicroelectronic substrate 110 (FIG. 9), which can increase theuniformity with which the electrolytic process removes material from theconductive layer 111 (FIG. 9). The planarizing pad 582 can also haveabrasive particles 589 for planarizing the microelectronic substrate 110in the manner described above with reference to FIG. 9. Furthermore, theplanarizing pad 582 can filter carbon or other material that erodes fromthe electrodes 520 a and 520 b to prevent the electrode material fromcontacting the microelectronic substrate 110. Still further, theplanarizing pad 582 can act as a sponge to retain the electrolyte 531 inclose proximity to the microelectronic substrate 110.

FIG. 11 is a partially schematic, cross-sectional side elevational viewof a rotary apparatus 660 for planarizing and/or electrolyticallyprocessing the microelectronic substrate 110 in accordance with anotherembodiment of the invention. In one aspect of this embodiment, theapparatus 660 has a generally circular platen or table 680, a carrierassembly 690, a planarizing pad 682 positioned on the table 680, and aplanarizing liquid 687 on the planarizing pad 682. The planarizing pad682 can be a fixed abrasive planarizing pad or, alternatively, theplanarizing liquid 687 can be a slurry having a suspension of abrasiveelements and the planarizing pad 682 can be a non-abrasive pad. A driveassembly 695 rotates (arrow “G”) and/or reciprocates (arrow “H”) theplaten 680 to move the planarizing pad 682 during planarization.

The carrier assembly 690 controls and protects the microelectronicsubstrate 110 during planarization. The carrier assembly 690 typicallyhas a substrate holder 692 with a pad 694 that holds the microelectronicsubstrate 110 via suction. A drive assembly 696 of the carrier assembly690 typically rotates and/or translates the substrate holder 692 (arrows“I” and “J,” respectively). Alternatively, the substrate holder 692 mayinclude a weighted, free-floating disk (not shown) that slides over theplanarizing pad 682.

To planarize the microelectronic substrate 110 with the apparatus 660,the carrier assembly 690 presses the microelectronic substrate 110against a planarizing surface 688 of the planarizing pad 682. The platen680 and/or the substrate holder 692 then move relative to one another totranslate the microelectronic substrate 110 across the planarizingsurface 688. As a result, the abrasive particles in the planarizing pad682 and/or the chemicals in the planarizing liquid 687 remove materialfrom the surface of the microelectronic substrate 110.

The apparatus 660 can also include a current source 621 coupled withleads 628 a and 628 b to one or more electrode pairs 670 (one of whichis shown in FIG. 11). The electrode pairs 670 can be integrated with theplaten 680 in generally the same manner with which the electrodes 520 aand 520 b (FIG. 10) are integrated with the top panel 581 (FIG. 10).Alternatively, the electrode pairs 670 can be integrated with theplanarizing pad 682. In either embodiment, the electrode pairs 670 caninclude electrodes having shapes and configurations generally similar toany of those described above with reference to FIGS. 3-10 toelectrolytically remove conductive material from the microelectronicsubstrate 110. The electrolytic process can be carried out before,during or after the CMP process, as described above with reference toFIG. 9.

FIG. 12A is a schematic circuit representation of some of the componentsdescribed above with reference to FIG. 10. The circuit analogy can alsoapply to any of the arrangements described above with reference to FIGS.3-11. As shown schematically in FIG. 12A, the current source 521 iscoupled to the first electrode 520 a and the second electrode 520 b withleads 528 a and 528 b respectively. The electrodes 520 a and 520 b arecoupled to the microelectronic substrate 110 with the electrolyte 531 inan arrangement that can be represented schematically by two sets ofparallel capacitors and resistors. A third capacitor and resistorschematically indicates that the microelectronic substrate 110 “floats”relative to ground or another potential.

In one aspect of an embodiment shown in FIG. 12A, the current source 521can be coupled to an amplitude modulator 522 that modulates the signalproduced by the current source 521, as is shown in FIG. 12B.Accordingly, the current source 521 can generate a high-frequency wave804, and the amplitude modulator 522 can superimpose a low-frequencywave 802 on the high-frequency wave 804. For example, the high-frequencywave 804 can include a series of positive or negative voltage spikescontained within a square wave envelope defined by the low-frequencywave 802. Each spike of the high-frequency wave 804 can have arelatively steep rise time slope to transfer charge through thedielectric to the electrolyte, and a more gradual fall time slope. Thefall time slope can define a straight line, as indicated byhigh-frequency wave 804, or a curved line, as indicated byhigh-frequency wave 804 a. In other embodiments, the high-frequency wave804 and the low-frequency wave 802 can have other shapes depending, forexample, on the particular characteristics of the dielectric materialand electrolyte adjacent to the electrodes 420, the characteristics ofthe substrate 110, and/or the target rate at which material is to beremoved from the substrate 110.

An advantage of this arrangement is that the high frequency signal cantransmit the required electrical energy from the electrodes 520 a and520 b to the microelectronic substrate 110, while the low frequencysuperimposed signal can more effectively promote the electrochemicalreaction between the electrolyte 531 and the conductive layer 111 of themicroelectronic substrate 110. Accordingly, any of the embodimentsdescribed above with reference to FIGS. 3-11 and/or below with referenceto FIGS. 13-18 can include an amplitude modulator in addition to acurrent source.

FIG. 13 is a partially schematic, partially broken isometric view of aportion of an apparatus 1360 configured to electromechanically and/orelectrochemically-mechanically remove material from the microelectronicsubstrate 110 in accordance with another embodiment of the invention. Inone aspect of this embodiment, the apparatus 1360 includes a polishingmedium 1382 and a plurality of electrode pairs 1370. Each electrode pair1370 can include a first electrode 1320 a and a second electrode 1320 b,elongated along parallel axes 1390. The electrodes 1320 a and 1320 b caneach have a width W1 transverse to the axes 1390, and can be separatedby polishing pad portions 1383. Each polishing pad portion 1383 can havea width W2 transverse to the axes 1390, and can have an elongatedpolishing surface 1386. In one aspect of this embodiment, the polishingsurfaces 1386 of the pad portions 1383 project beyond the electrodes1320 a, 1320 b. Accordingly, the electrodes 1320 a, 1320 b can berecessed from the polishing surfaces 1386 by a recessed distance RD,while the polishing surfaces 1386 contact the microelectronic substrate110 to mechanically, electromechanically and/orelectrochemically-mechanically polish and/or planarize or otherwiseremove material from the microelectronic substrate 110. In oneembodiment, the recess distance RD can have a value of from about 0.1 mmto about 10 mm. In other embodiments, the recess distance RD can haveother values, depending, for example, on the particular geometries ofthe electrodes 1320 a, 1320 b and the pad portions 1383.

In another aspect of this embodiment, the pad portions 1383 can includeflow passages 1384, each of which has an aperture 1385 proximate to thecorresponding polishing surface 1386. The flow passages 1384 are coupledto a supply conduit 1337, which can in turn be coupled to anelectrolytic fluid reservoir (not shown in FIG. 13). In one embodiment,the flow passages 1384 can be discrete linear passages between theconduit 1337 and the polishing surface 1386, as shown in FIG. 13. Inanother embodiment, the pad portions 1383 can be generally porous, andthe flow passages 1384 can include a network of interconnected,convoluted paths. In any of these embodiments, the flow passages 1384can provide an electrolyte 1331 (such as an electrolytic fluid) at leastproximate to an interface between the microelectronic substrate 110 andthe polishing surfaces 1386.

In one embodiment, the pad portions 1383 can include polyurethanematerials or other suitable materials, such as those incorporated inpolishing pads available from Rodel, Inc. of Phoenix, Ariz. In oneaspect of this embodiment, the width W1 of the pad portions 1383 can beless than the width W2 of the interstitial electrodes 1320 a, 1320 b toallow for sufficient electrical communication between the electrodes1320 a, 1320 b and the microelectronic substrate 110. In otherembodiments, the electrodes 1320 a, 1310 b and the polishing padportions 1383 can have other relative dimensions depending on theparticular geometries of these components.

One feature of an embodiment of the apparatus 1360 shown in FIG. 13 isthat the electrodes 1320 a, 1320 b are recessed from the polishingsurfaces 1386. Accordingly, the electrodes 1320 a, 1320 b can be inelectrical contact with the microelectronic substrate 110 via theelectrolyte 1331 without coming into direct physical contact with themicroelectronic substrate 110. In one aspect of this embodiment, thesurfaces of the electrodes 1320 a, 1320 b facing toward themicroelectronic substrate 110 are exposed to provide direct electricalcontact with the electrolyte 1331. In other embodiments, the electrodes1320 a, 1320 b can be enclosed or partially enclosed with a protectivefilm or other structure that can protect the electrodes 1320 a, 1320 bwhile still permitting electrical communication between the electrodes1320 a, 1320 b and the microelectronic substrate 110 via the electrolyte1331.

Another feature of an embodiment of the apparatus 1360 shown in FIG. 13is that the electrolyte 1331 can be provided at least proximate to (andin some embodiments, directly to) an interface between the polishingsurfaces 1386 and the microelectronic substrate 110. Accordingly, theelectrolyte 1331 can lubricate the interface between the microelectronicsubstrate 110 and the polishing surfaces 1386, chemically promotematerial removal from the microelectronic substrate 110, and/or conveyremoved particles away from the interface. At the same time, theelectrolyte 1331 can fill the recesses between neighboring pad portions1383 to provide electrical communication between the electrodes 1320 a,1320 b and the microelectronic substrate 110, thus facilitatingelectrically removing material from the microelectronic substrate 110.

FIG. 14 is a partially schematic, partially broken isometric view of aportion of an apparatus 1460 configured in accordance with anotherembodiment of the invention. In one aspect of this embodiment, theapparatus 1460 includes electrode pairs 1470 with first electrodes 1420a and second electrodes 1420 b. The electrodes 1420 a, 1420 b includeflow passages 1484 having apertures 1485 for providing the electrolyte1331 proximate to the surface of the microelectronic substrate 110.Accordingly, the flow passages 1484 are connected to a supply conduit1447 which is in turn coupled to an electrolytic fluid source.

In one aspect of this embodiment, each electrode 1420 a, 1420 b isspaced apart from its neighbor by a dielectric layer 1429. Thedielectric layer 1429 can terminate at a plane flush with the upperfaces of the electrodes 1420 a, 1420 b. A polishing medium 1482 can thenbe positioned against the electrodes 1420 a, 1420 b and the upwardlyfacing edges of the dielectric layers 1429. In one aspect of thisembodiment, the polishing medium 1482 can include a sub-pad 1487 whichsupports pad portions 1483. Each pad portion 1483 can include apolishing surface 1486 that contacts the microelectronic substrate 110in a manner generally similar to that described above. In a furtheraspect of this embodiment, the sub-pad 1487 can include aperturesaligned with the flow passage apertures 1485 to permit uninhibited flowof the electrolyte 1331 from the flow passages 1484. In anotherembodiment, the sub-pad 1487 can have a porous composition that helps todistribute the electrolyte 1331 in the interstices between neighboringpad portions 1483. In still another embodiment, the sub-pad 1487 can beeliminated, and the pad portions 1483 can be integral with thedielectric layers 1429 in an arrangement generally similar to thatdescribed above with reference to FIG. 13.

One feature of an embodiment of the apparatus 1460 shown in FIG. 14 isthat the apertures 1485 of the flow passages 1484 are recessed away fromthe interface between the microelectronic substrate 110 and thepolishing surfaces 1486. Accordingly, the electrolyte 1331 can flowfreely out of the flow passages 1484 despite the presence of themicroelectronic substrate 110.

FIG. 15 is an isometric view of a portion of an apparatus 1560 havingelectrodes 1520 a, 1520 b and a polishing medium 1582 arranged inaccordance with another embodiment of the invention. In one aspect ofthis embodiment, the polishing medium 1582 includes polishing padportions 1583 that project beyond the electrodes 1520 a, 1520 b. Eachpolishing pad portion 1583 includes a polishing surface 1586 and aplurality of flow passages 1584. Each flow passage 1584 has an aperture1585 proximate to the polishing surface 1586 to provide an electrolyte1331 proximate to an interface between the microelectronic substrate 110and the polishing surface 1586. In one aspect of this embodiment, thepad portions 1583 can include recesses 1587 surrounding each aperture1585. Accordingly, the electrolyte 1331 can proceed outwardly from theflow passages 1584 while the microelectronic substrate 110 is positioneddirectly overhead.

FIG. 16 is an isometric view of a portion of an apparatus 1660 having apolishing medium 1682 configured in accordance with yet anotherembodiment of the invention. In one aspect of this embodiment, thepolishing medium 1682 includes a polishing pad 1683 and sub-pad 1687positioned against first electrodes 1620 a and second electrodes 1620 b.The electrodes 1620 a, 1620 b are separated by a dielectric layer 1629.The dielectric layer 1629 includes flow passages 1684 having apertures1685 to deliver the electrolyte 1331 proximate to an interface betweenthe polishing medium 1682 and the microelectronic substrate 110 (FIG.15).

In one aspect of this embodiment, the polishing medium 1682 includes apolishing surface 1686 having a plurality of recesses 1689. The recesses1689 can extend entirely through the polishing pad 1683 and the sub-pad1687 to expose both the apertures 1685 and the upwardly-facing surfacesof the electrodes 1620 a, 1620 b. Accordingly, the recesses 1689 canprovide for an uninhibited flow of electrolyte 1331 from the apertures1685, and can provide for electrical communication (via the electrolyte1331) between the electrodes 1620 a, 1620 b and the microelectronicsubstrate 110. The polishing medium 1682 can further include transversechannels 1688 that connect adjacent recesses 1689 and allow theelectrolyte to pass from one recess 1689 to the other without beinginhibited by the microelectronic substrate 110.

In one aspect of an embodiment described above with reference to FIG.16, the recesses 1689 can have a generally oval planform shape. In otherembodiments, the recesses 1689 can have other shapes (such as circularshapes) that allow for the flow of the electrolyte 1331 from theapertures 1685, and that allow for electrical communication between theelectrodes 1620 a, 1620 b and the microelectronic substrate 110 via theelectrolyte 1331. Accordingly, the recesses 1689 can extend entirelythrough the polishing pad 1683 and the sub-pad 1687 (as described above)or, in another embodiment, the recesses 1689 can extend through thepolishing pad 1683 but not through the sub-pad 1687. The sub-pad 1687can accordingly have a porous composition that allows the electrolyte1331 to diffuse from the apertures 1685, through the sub-pad 1687 andinto the recesses 1689.

FIG. 17 is a top isometric view of an apparatus 1760 configured inaccordance with still another embodiment of the invention. In one aspectof this embodiment, the apparatus 1760 includes electrode pairs 1770,each having a first electrode 1720 a spaced apart from a secondelectrode 1720 b. The apparatus 1760 can further include a polishingmedium 1782 that has pad portions 1783 projecting beyond theupwardly-facing surfaces of electrodes 1720 a, 1720 b. Accordingly, theelectrodes 1720 a, 1720 b and the polishing medium 1782 can removematerial from the microelectronic substrate 110 in a manner generallysimilar to that described above.

The microelectronic substrate 110 can have a diameter D and theapparatus 1760 can have a length L and a width W, both of which aregreater than the microelectronic substrate diameter D. Accordingly, themicroelectronic substrate 110 can be moved about over the polishingmedium 1782, all the while being in electrical communication with atleast some of the electrodes 1720 a, 1720 b. As the microelectronicsubstrate 110 moves, different pairs of electrodes 1720 a, 1720 bprovide electrical communication with the microelectronic substrate 110.

In a further aspect of this embodiment, the electrodes 1720 a, 1720 band the pad portions 1783 are elongated parallel to an axis 1790. Themicroelectronic substrate 110 can move relative to the polishing medium1782 back and forth in a direction indicated by arrow A. In a furtheraspect of this embodiment, an angle Θ between arrow A and axis 1790 canbe 90° or less. In one particular embodiment, Θ can have a value ofabout 45°. Accordingly, the microelectronic substrate 110 can moveacross a plurality of electrical fields generated by a correspondingplurality of electrode pairs 1770 during processing. An advantage ofthis arrangement is that the uniformity with which material is removedfrom the microelectronic substrate 110 can be increased relative to anarrangement in which the center of the microelectronic substrate 110does not move relative to the polishing medium 1782.

FIG. 18 is a top isometric view of an apparatus 1860 configured inaccordance with yet another embodiment of the invention. In one aspectof this embodiment, the apparatus 1860 has electrode pairs 1870, each ofwhich includes a first electrode 1820 a and a second electrode 1820 b.Adjacent electrodes 1820 a, 1820 b are separated by dielectric layer1829. The apparatus 1860 can further include a polishing mediumgenerally similar to any of those discussed above, but not shown in FIG.18 for purposes of clarity.

In a further aspect of this embodiment, the electrodes 1820 a, 1820 bcan have a herringbone or chevron shape, and can be arrangedcircumferentially to define a rectangular field. For example, eachelectrode 1820 a, 1820 b can include an apex or angled portion 1821 andfirst and second portions 1822, 1823 extending from the apex or angledportion 1821. The first and second portions 1822, 1823 can define anincluded angle having a value of 180° or less. In a particularembodiment, a can have a value of about 90° and in other embodiments, acan have other values. In any of these embodiments, when themicroelectronic substrate 110 (FIG. 17) moves relative to the electrodes1820 a, 1820 b, the microelectronic substrate 110 is exposed to aplurality of electrical fields generated by the plurality of electrodepairs 1870. As discussed above with reference to FIG. 17, an advantageof this arrangement is that the uniformity with which material isremoved from the microelectronic substrate 110 can be improved.

From the foregoing, it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. For example, other embodiments ofthe polishing media (shown in FIGS. 13-18 as facing upwardly to contacta downwardly facing surface of the microelectronic substrate) can facedownwardly to contact an upwardly facing surface of the microelectronicsubstrate. Other embodiments of the apparatuses described above includecombinations of features shown in separate Figures. For example, anapparatus in accordance with one embodiment includes liquid flowpassages in both the polishing medium and the electrodes. The liquidflow passages can be coupled to the same or different sources of liquid.Accordingly, the invention is not limited except as by the appendedclaims.

1. An apparatus for removing material from microelectronic substrates,comprising: a support member configured to releasably carry amicroelectronic substrate; a first electrode spaced apart from themicroelectronic substrate when the microelectronic substrate is carriedby the support member; a second electrode spaced apart from themicroelectronic substrate when the microelectronic substrate is carriedby the support member, the second electrode being spaced apart from thefirst electrode, with at least one of the electrodes being coupleable toa source of varying electrical signals; and a polishing medium, at leasta portion of which is positioned between the electrodes and the supportmember, the polishing medium having a polishing surface positioned tocontact the microelectronic substrate when the microelectronic substrateis carried by the support member, wherein at least a portion of thefirst and second electrodes is recessed from the polishing surface. 2.The apparatus of claim 1 wherein the polishing medium includes apolishing pad material.
 3. The apparatus of claim 1 wherein thepolishing medium includes a plurality of flow passages coupleable to asource of liquid, and wherein each flow passage has an aperture at leastproximate to the polishing surface, the apertures being positioned todispense the liquid at least proximate to the polishing surface.
 4. Theapparatus of claim 1 wherein the first and second electrodes face towardthe support member.
 5. The apparatus of claim 1 wherein the firstelectrode, the second electrode and a portion of the polishing mediumbetween the first and second electrodes are elongated along parallelaxes.
 6. The apparatus of claim 1 wherein the first electrode, thesecond electrode and a portion of the polishing medium between the firstand second electrodes are elongated along generally straight, parallelaxes.
 7. The apparatus of claim 1 wherein the polishing medium includesa polyurethane material.
 8. The apparatus of claim 1 wherein the firstand second electrodes are recessed from the polishing surface by adistance of from about 0.1 millimeter to about ten millimeters.
 9. Theapparatus of claim 1 wherein the microelectronic substrate has adiameter and the first and second electrodes each have a length greaterthan the diameter.
 10. The apparatus of claim 1 wherein the firstelectrode has a length and a first width less than and generallytransverse to the length, and wherein the polishing medium has a secondwidth that is less than the first width.
 11. The apparatus of claim 1wherein the first electrode has a plurality of flow passages coupleableto a source of liquid, and wherein each flow passage has an apertureproximate to the polishing medium, the apertures being positioned todispense the liquid proximate to the polishing surface.
 12. Theapparatus of claim 1 wherein the polishing medium has a plurality offlow passages coupleable to a source of liquid, and wherein each flowpassage has an aperture proximate to the polishing surface, furtherwherein the polishing medium includes a recess proximate to eachaperture, the recess being offset from the polishing surface.
 13. Anapparatus for removing material from microelectronic substrates,comprising: a support member configured to releasably carry amicroelectronic substrate; a first electrode spaced apart from themicroelectronic substrate when the microelectronic substrate is carriedby the support member; a second electrode spaced apart from themicroelectronic substrate when the microelectronic substrate is carriedby the support member, the second electrode being spaced apart from thefirst electrode, with at least one of the electrodes being coupleable toa source of varying electrical signals; and a polishing medium, at leasta portion of which is positioned between the electrodes and the supportmember, the polishing medium having a polishing surface positioned tocontact the microelectronic substrate when the microelectronic substrateis carried by the support member, wherein the polishing medium has atleast one opening aligned with the first and second electrodes, theopening being positioned to allow electrical communication between theelectrodes and the microelectronic substrate when the microelectronicsubstrate is carried by the support member.
 14. The apparatus of claim13 wherein the first and second electrodes face directly toward thesupport member.
 15. The apparatus of claim 13 wherein the first andsecond electrodes face directly toward the support member with adielectric material disposed between the first and second electrodes andthe support member.
 16. The apparatus of claim 13 wherein the openinghas a generally oval shape.
 17. The apparatus of claim 13 wherein thepolishing medium includes a plurality of flow passages coupleable to asource of liquid, and wherein each flow passage has an aperture at leastproximate to the polishing surface, the apertures being positioned todispense the liquid at least proximate to the polishing surface.
 18. Theapparatus of claim 13 wherein the polishing medium has a plurality offlow passages coupleable to a source of liquid, and wherein each flowpassage has an aperture proximate to the polishing surface, furtherwherein the opening of the polishing medium is aligned with theapertures.
 19. The apparatus of claim 13 wherein the first electrode,the second electrode and the polishing medium are elongated alongparallel axes.
 20. The apparatus of claim 13 wherein the first andsecond electrodes are recessed from the polishing surface.